The HL-A system in asbestos workers

Our plain-English summary of The HL-A system in asbestos workers, by J.A. Merchant, P.T. Klouda, C.A. Soutar, et al (British Medical Journal, 1975).

The study

• Authors: J.A. Merchant, P.T. Klouda, C.A. Soutar, W.R. Parkes, S.D. Lawler, M. Turner-Warwick
• Journal: British Medical Journal
• Published: 1975;1(5951):189-91
• Cited by: 50 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001132).

Abstract

In a study of the HL-A system in 56 selected asbestos workers referred to the Pneumoconiosis Medical Panel with definite or suspected asbestosis, the W 27 antigen was found more often than among a control population. Six of the 10 asbestos workers with the W 27 antigen had definite radiographic evidence of asbestosis compared to 13 out of 46 without the W 27 antigen. These observations, if confirmed, suggest that the W 27 antigen may provide a useful marker of an enhanced susceptibility to the tissue-damaging effects of asbestos dust.

In plain English

This pilot study looked at the HL-A system, which the article describes as the major human histocompatibility (tissue-type) system, in 56 selected asbestos workers. They had been referred to the Pneumoconiosis Medical Panel because of suspected asbestosis. Most had worked as laggers in the insulation industry or in dockyards. All were Caucasian and all but one were men. Their HL-A types were compared with those of 153 normal Caucasian donors. The antigen W 27 was three times more common among the asbestos workers than among the controls, a statistically significant difference, though the authors noted this was not corrected for the number of antigen types tested. Six of the 10 workers with W 27 had moderate to severe asbestosis on chest X-ray, compared with 13 of the 46 without it. This difference was not statistically significant. Workers with W 27 tended to have had shorter exposure. No association was seen between W 27 and pleural shadows. The authors called the results preliminary. They concluded that, if confirmed, W 27 may mark people with increased susceptibility to lung damage from asbestos dust.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Pilot study comparing HL-A antigen frequencies in asbestos workers with a control population of normal donors
• Who was studied: 56 selected asbestos workers referred to the Pneumoconiosis Medical Panel with suspected asbestosis. All were Caucasian and all but one were men. Mean age was 57 years (range 37-72). Controls were 153 normal Caucasian donors previously typed for HL-A antigens at the Royal Marsden Hospital.
• Exposure: Occupational asbestos exposure, mainly as laggers in the insulation industry or in dockyards. Fiber type was not stated. Mean duration of exposure was 22 years (range 1-47) and mean time since first exposure was 31 years (range 12-52).
• Main results:
  • W 27 was three times more common among the 56 asbestos workers than among the 153 controls. This was reported as statistically significant, but not corrected for the number of specificities tested.
  • 6 of the 10 workers with W 27 had moderate to severe asbestosis on radiograph, compared with 13 of the 46 workers without W 27.
  • The apparent association between W 27 and severity of asbestosis did not reach statistical significance in this small group.
  • Overall, 37 of the 56 workers were judged to have little or no radiographic evidence of asbestosis, and 19 were judged to have moderate to severe asbestosis.
  • Workers positive for W 27 tended to have been exposed for a shorter period, and their first exposure was more recent. The authors stated that the W 27 association with severe asbestosis cannot be attributed to longer exposure.
  • No apparent association was found between W 27 and pleural shadows.
  • HL-A 9 was less frequent among the asbestos workers, but not statistically significantly so.
  • Antinuclear antibody and rheumatoid factor did not seem to be associated with W 27 or any other antigen.
• The authors' conclusion: The authors concluded that, if confirmed, the association between W 27 and severity of asbestosis suggests the antigen may provide at least one marker for identifying individuals with increased susceptibility to the tissue-damaging effects of asbestos dust on the lung.
• Limitations the authors state:
  • The authors described the results as preliminary and planned a study of a larger population.
  • The study group was small and selected.
  • The significance test for W 27 was not corrected for the number of antigen specificities tested.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Pneumoconiosis.

Related studies

• Frequency of HLA antigen in asbestos workers with and without pulmonary fibrosis — C.C. Evans, H.C. Lewinsöhn, et al. (1977)
• HLA-A and B antigen frequencies in an asbestos exposed population with normal and abnormal chest radiographs — C. Darke, M.M. Wagner, et al. (1979)
• Diagnosing tumours on routine surgical sections by immunohistochemistry: use of cytokeratin, common leucocyte, and other markers — R.N. Poston, Y.S. Sidhu (1986)
• Failure to demonstrate tumour-associated transplantation antigens on asbestos-induced mesotheliomas in rats — D.G. Brown, J.C. Wagner, et al. (1980)
• HLA-A and B antigen frequencies and mesothelioma in relation to asbestos exposure — M.M. Wagner, C. Darke, et al. (1983)
• Asbestos exposure among Seoul metropolitan subway workers during renovation of subway air-conditioning systems — I.J. Yu, C.Y. Yoo, et al. (2004)

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